How to Make It
Melt 1 cup unsalted butter in a saucepan over medium-high; bring to a boil. (The water content of the butter will foam and begin to evaporate.) Reduce heat to medium-low; simmer until solids sink to the bottom of the saucepan, 5 minutes. Pour through a fine wire-mesh strainer lined with cheesecloth or a coffee filter; discard solids.